This is a discussion on I changed my plugs and now my car runs like crap... What happened? within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; So I'm a newbie, and I did my first spark plug swap on an 03 Wrx. I reviewed the tutorial ...

I changed my plugs and now my car runs like crap... What happened?

So I'm a newbie, and I did my first spark plug swap on an 03 Wrx. I reviewed the tutorial that was posted on this site... (Very Helpful by the way) After I put everything back together and fired it up for the first time, it sounds like I'm only running on 2 cylinders. My first thought is that I put the coil packs back in the wrong place and the engine is miss firing as a result. Is this even possible? If so How do I know which coil pack is in the wrong place. I'm nervouse to drive it somewhere to have it checked. Aslo, I gapped my Autolite Double Platinum plugs to .028. Could that be causing any problem?

What kind of plugs did you use, the manual says .028-.031. I just did mine today and put them at .030 and its running great. You did thread them in by hand first right? I dont think you can put the coil packs in wrong cause on my 04 they are fixed to the engine where the 2 wires for each side meet up. Besides you wouldnt be able to screw them in cause they have to be in a certain way. But if they are not fixed in place, I would recomend doing them one at a time. Take pack off, then plug, put new plug in. Make sure its gapped, then put the pack back on. Do the next one.

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I just did the plugs on my wrx today. I took a marker and put a dot on both the rear coil packs or whatever you call them so they went back correctly. Did a compression test too. Very happy with the results.

The coilpacks are interchangeable from cylinder to cylinder. Make sure you have everything installed/torqued properly. Make sure all the wiring clips are fully plugged into the coilpacks. Make sure you have the front clips on the front coilpacks, rear clips on the rear coilpacks.

For what it's worth, the platinum plugs are not the best upgrade. Most people have the best results with either stock style NGK Iridium at .030" or copper plugs gapped anywhere from .030 down to .028. Unless you're running more than 20psi of boost, I'd leave the gap at .030". More boost requires a tighter gap in most applications.

If you double check ALL your work and really think you did it 100% correctly, see if you have any CEL's. If you do get some misfire CELs, try swapping a coilpack around from cylinder to cylinder. If the misfire CEL follows the coilpack, it's likely a bad coilpack. Not sure why it would have gone bad just because you changed the plugs, but they're not invincible and have been known to go bad unexpectedly.

Yea also I dont know if its what Timdog1650 was talking about when he said clips, but on my 04, the 2nd coilpack. That would be the rear one if your standing at the nose of the car looking to the rear. It has a clip like attachment on it that you have to remember to screw in with the pack. I only have one. Dont know how many your year ride has. You rememeber to put it back on. It should go on the outside of the pack.

I just did the plugs on my wrx today. I took a marker and put a dot on both the rear coil packs or whatever you call them so they went back correctly. Did a compression test too. Very happy with the results.

What did your compresion test #'s look like? Racechaser, If all else fails with the packs, you might want to do a compression test. Just an idea.

do you have to use the spark plug gel. cant remember wat its called but you usually put in the boot of the wires. iknow we dont have wires but, maybe you might need that goop. from wat i read it also improves the connectivity from the plug to the coil pack. also make sure the coil pack is completely bolted down thats probably the ground,

do you have to use the spark plug gel. cant remember wat its called but you usually put in the boot of the wires. iknow we dont have wires but, maybe you might need that goop. from wat i read it also improves the connectivity from the plug to the coil pack. also make sure the coil pack is completely bolted down thats probably the ground,

No gel or anything required, the stock system works simply by plugging the harness into the coilpack (which is the name of the rubber boot that bolts to the heads and covers the spark plug).

The only thing you might consider is using a very sparing amount of anti-seize on the plug itself so it does not get stuck in the head.

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